Fecundity calendar



T. scHENK ETAL 2,577,544

FECUNDITY CALENDAR 2 SHEETS-SHEET 1 12 IO 2g 21 22 23 29 25 2627QZQBOI-lg/B 34 3556.37 35 39 Q0 ql Dec. 4, 1951 Filed March l, 1949INVENTORS Theresia .Schenk aria Spr P BY M und.

AGENT Dec., 4 1951 T. scHENK ETAL 2,577,544

FECUNDITY CALENDAR Filed March l, 1949 2 SHEETS-SHEET 2 INVENTORSTheres/0, Schenk Maria spruzzo',

AGENT Patented Dec. 4, 1951 FECUNDITY CALENDAR Theresia Schenk and MariaSprung, Graz, Austria, assignors, by direct and mesne assignments, ofone-halt` to Hans Schenk, Graz, Austria, and one-half to .l ames Jovan,Chicago, Ill.

Application March 1, 1949, Serial No. 78,992 In Austria April 5, 1948(Cl. 23S- 86) 18 Claims.

This invention relates to an improvement in fecundity calendars andessentially consists in certain peculiarities of the construction andarrangement of masks for indicating the fecundity days appearing on acalendar band substantially as will be hereinafter more fully set forthand claimed.

First the invention is explained by means of diagrammatic Figures 1 and2. Figs. 3-'7 illustrate an embodiment by way of example of thefecundity calendar in the shape of a iiat box, Fig..3 showing a sectionaccording to line III-Iii of Fig. 4, Fig. 4 a section according to lineIV--IV of Fig. 3, Figs. 5 and 6 a side view and a front view,respectively, of the box, and Fig. 'l a View of a circular platearranged in the box, Figs. 8 and 9 are illustrating a modifiedembodiment of the calendar with coils for rolling and unrolling thecalendar band, Fig. 8 showing a middle section through the co-axialcoils for rolling up and unrolling, and the circular guide path for theband, and Fig. 9 a cross section similar to` that of Fig. 4.

Figs. l, 2 were based upon a case by way of example assuming that thedetermination of the fertile and sterile days of a woman is concerned,whose menstruation has commenced on the third day of a month, supposinga menstrual cycle varying from 29 to 31'days.

The fecundity calendar shows a calendar band I of a transparent or of anopaque flexible material, upon which the dates are. continuouslyregistered in equal succession and which for example is arranged in acasing. Band I is suitably passed possibly closely underneath or above alixed transparent window 2 for example in said casing for said band, oran opaque adjusting mark; The window has the width of a date inscriptionupon the band I, i. e. of the calendar calibration Said adjusting window2 is colored, so that the calendar date, being in a position covered bysaid window, appears in the color of said adjusting window.

Parallel to the band I two similar figure scales 3, 4 are for example onsaid casing fixedly arranged, starting according to Fig. l at theadjusting window 2. The individual .figures of said scales 3, 4 show thenumber of days during which the feminine menstrual cycle may last; as anabsolute minimum 20 days, and as an absolute maximum 4l days are beingthereby assumed. Therefore only the days from 20 to 41 were insei-ted,the preceding gures up to the window 2 having been left out. menstrualcycle there is to be comprehended the bil number of days lying betweenthe commencingV day of one menstruation and the commencing day of themenstruation directly following, whereby both said commencing days areto be also counted The distance of the figures of the scales 3, 4, fromone another i. e. of their calibration, is corresponding to the distanceof dates of the calendar band I. The arrangement of two ligure Scales 3,4 is intended for using, if in the case concerned a varying menstrualcycle is. to be considered, one gure scale for the shortest, the otherligure scale for the longest menstrual cycle,`

whereby it is, according to the invention, completely irrelevant, whichof the ligure scales serves for the one, and which for the othermenstrual cycle.

With window 2 both scales 3, 4, two indicating devices 5, 6, forexample, rings in the abovementioned casing, for the fecundity daysslidably coact, said devices comprising the adjusting windows II, I2cooperating with the scales 3 ori 4, and the masks 1, 8 indicating thefecundity dates on the band I. The indicating devices 5, 6 may be movedin the longitudinal direction of the band I, and be xed in the adjustedposition by a conventional xing means 5a, 6a each including screwsclamping the indicating devices to the band. With a varying menstrualcycle the one indicating device is used for the longest, and the otherfor the shortest menstrual cycle,` whereby it isaccording to theinvention, completely irrelevant, which of both indicating devices isbeing used for the one, and which for the other menstrual cycle, becauseboth devices 5 and 6 are constructed in similar manner.

The windows II, I2 are covering, at a time, one single iigure of thescales 3, or 4 only, so that in the window thus appears only one number,while the remaining part of the scales is covered by the indicatingdevice.y The masks 'I, 8 are for the range of the fertile dates of onecolor, or otherwise surface-like marked, e. g. by hatching, the parts ofthe band I covered by said masks appearing in color, said parts being,together with said band, brought into a covered position by By the termfeminine the adjusting procedure. The parts of the mask indicating thefollowing dates of menstruation shouldsuitably be of different color.The masks may be transparent or opaque, according to whether they cometo lie above the band I or, if a transparent band is used, beneath saidtransparent band.

As fecundity days, l1 days are being assumed, comprising thephysiologically implied period` of 8 fecundity days, and further 3 daysadded for reasons of expediency. Said period of 8 days or anothershorter period lying within said 11 days, which period may be lookedupon as especially fertile, may still additionally be marked, e. g. bycrossed lines, a special coloring or vthe like. The last day of thefecundity period is again distant 11 days from the commencing date ofthe menstruation directly following.

The mode of operation of the fecundity calendar according to Fig. 1 isas follows:

Band I' is being drawn until thedateof 'the commencing of themenstruation appears in the window 2, then the indicating deviceismoved, until the number of the longest or of the shortest menstrualcycle known tov any woman, e. g. 29 and 3l, appears in the window I I,or I2.l Both commencing dates of the following menstruation are denotedby 9, I0. Their distance from the adjusting window 2 measured in days isthus to bef'seen inthe-'windows II,' I2. The fecundity days areindicated in color' by the masks 1,! 8150i the indicating device uponthey band I, i. e. by theltotal part of the band covered by'theoverlapping masks, said part is indicated in the? drawing by equalhatching.

If, on the contrary,.a woman rwith'an ever constant, toa day regularmenstrual cycle is con` cerned, each of both indicating windows 'I I, I2is adjusted to this singlefmenstrualcycle.

The: adjusting'andreading procedure is-thus, With .theA subject ofrltheinvention,y very' simple. A'ast and faultless reading of the period isenabled by the'fact vthat-it appears for the user `in color, i..e. infulloptical covering of any date, the masksv 1, 8 being suitably ofequal color.

The construction according to Fig. 2 equals the construction accordingto Fig. 1, distinguishing merely inthe arrangement of the similar scalesI3, I4 for'the menstrual `cycles `and of the'reading windows I5,"I6.While, namely, with the embodiment according toFig; 1 the commencingdate of the'next' following'menstruaticn, denoted by 9, or IIII, and the'reading window II, or I 2; aref at an equal distance withvthe'indicating device' 5,v

orf 6,'from the adjusting window'2, the date denoted by S, or` I0; is,according to Fig;` 2, at a distance-from the adjusting window 2differing from the distance of 'the reading window I 5, or I6. `Thescales I3, I4 `arelikewise displaced,"accordingly. d

Thereby, howeveiyno change is effected as to the principal relations of`the row of figures and'of thev adjusting and reading devices,respectively, with regard to one another. The arrangement accordingtcFiggZ is intended forcompletely excluding rthe possibility ofconfusions as' to adjustingfiand to readingywhich possibility lcouldperhaps, according to Fig.v l, still be secnin the factv that in thethree columns of` figures namely: the series rof dates onf the calendarband Il and both figure scales 3,' 4 toov great aV number of'gures ofequal size is passing directlynextto one another.

In Fig.i2 there is'schematically illustratedV a separate arrangement ofsaid three columns of figures. With an embodiment of the invention,e.'g. according to Figs. v3'-'7,^'said separation'is realized in -such amannerthat the calendar band is guided over a central circular path;while both scales of figures are, each, arranged laterally from Y saidpath, so that theuser, in consequence ofthe Ythree dimensionalseparation cf'said parts, al-

ways has Vone single column of gures only before her eyes,conusionsbeing thus avoided.

' The manipulation of 'the fecundityfcalendarac-f 4 cording to Fig. 2 issimilar vto that according to Fig. 1.

When adjusting the date of the calendar band I, on which themenstruation has commenced, to the adjusting window 2, and when furtheradjustingl both windows I5, I6 to those numbers of the gurefscales `I3,I4 corresponding to the shortest, or longest duration of a varyingmenstrual cycle of the woman concerned, both terms 9Irmust-be distantfrom the adjusting window 2 by so many calendar days as is indicated bythe numbers ofithe 'figure' scales I3, I4 adjusted in both windows I5,I6.

The vembodiment of the fecundity calendar illustrated in Figs. 3 to 7 isconstructed according tothe embodiment of Fig. 2, and shows the shape ofa ilatbox. Said box is either circularly cylindrical,. as illustrated,it may, however, also be ovaleshaped o1' rectangular, square or of someother shape out of round. Together with a handy construction'fsaidshaping. has, according tozthe invention, likewise' the technicaladvantage Vthat the calendarxmay begthanks to said shaping;kept

especially small in its main dimensions. The

duration of :the absolutely longestmenstrual cy.-

cle is, as.. already mentioned, 41 days. These 41 days represent on thebasis of the calendanband calibration according tov Fig. 1 or 2 aconsiderable distance, because the date iigures onthe vcalendar bandmust still'be well legible, andtherefore must not be too small. 1n orderto enable thatthe calendar be considerably smaller, said distance of 41'days is not stretched out in a straight line, but arranged-as a circulararc along a cylindric'path.-

In adjusting the. guide vof the :calendar band to the form of a circulararc also; the other partssof theV fecundity" calendar.v are (made :in avcircular form. Inwconsequ'ence; of 'said centricalA .arrange-l mentthere is now, asopposedto the straight arrangementaccording to. Fig. lor2, an accordance of4 vthe .calibrations of the individual., .calendarparis...

It should be possible to move the calendar bandv and.'V both indicating`devices: for Athe; fecundity dates with regard :to one another Withoutdisturbances; any of .said three parts possessing a certain strength ofmaterial. There follows that any cneof :them alscfhas, with aconcentricarrangement, a diirerent radius. This. effects, however, thatthe calibrations of the ycalendar band, ofthe figure scales `and ofvvthe masks, and the din'iensions of the windows must no longer be ofequal length,

but must; with. a decreasing radius, become .prog

leaves the box through the Aslot 20. The circular.

path I essentially extends over the rangeofV a cycle, upon which theAecundity days may be read,A as isprovided for enabling thereadingindependent'of the winding radius decreasing. during vtheunrolling of the band from the coil. forefthe bandleaves the box, aspringv 25 is acting brake-.likerthereupon The path .Ie maybedesigned'inthe manner of a reiiector,` shining or reflecting, in' ordertomake the band Pappear brighter. The part of the calendar band I whichis, at aitime, unrolled, is at the outside suitably out on or torn offytheslot 20 in such-a way, that Be-v the remaining end may still be wellseized. By means of the knob 2l resting upon the axle ZIa of the reel I1the calendar band may, if desired, be again rolled back into the insideof the box. At each side of the reel I1 with the rolled up band I thereis arranged a fixed circular plate 23, and 24, respectively. Both saidplates are joined together by a distance ring 26 with the aid of thescrews 21, and form the supporting structure of the box. Concentric tothe reel aXis'ZIa there are in said plates rotatably supported by meansof the screwed sleeves 33, 34, and 35,35, respectively, the outsidediscs 29, 30, which may be gradually turned round corresponding to thecalibration of the calendar, with the use of a ball stoppingarrangement. The ball stopping arrangement comprises the balls 32, lyingdiametrically opposite each other in an opening in each, of the discs23, 24, and engaging by the coil spring 3l, provided in a bore hole ofthe distance ring 26, recesses 28a of the rotatable discs 29, 30, saidrecesses being arranged upon a circular line at a distance from oneanother. Corresponding to the variations of the cycle from 2i) to 4I atleast 22 recesses are provided. By the use of a coil spring 3l for twoballs lying opposite each other an equal pressure is exerted upon saidballs, so that the effort required for the rotation of both discs islikewise equal. The outside circumference of the distance ring 2e formsthe said path I 9 for the band I. A spring 22 presses the reel I1 forthe band I against the fixed circular plate 23, in order to attain thefriction required for braking the reel. Both gure scales I3, I4 arearranged as a circular arc (Fig. 7) outside both fixed circular plates23, 24 as near as possible to the periphery, both Windows I5, I6 forsaid scales being situated in both rotatable circular discs 29, 30 (Fig.5)`.' The rotatable circular discs 29, 3U are performing, with .1;

this arrangement, the function 0f the indicating devices 5, 6 accordingto Figs. 1, 2.

The rotatable circular discs 29, 3|] adjustable by hand have near theiroutside circumference transparent walls projecting vertically,circularly bent, and arranged concentrically to the path I 9, said wallsforming the masks 1, 8, for the dates of the directly followingcommencement of menstruation; they are in the corresponding placesprovided with different transparent colors, but are otherwise colorlesstransparent. For facilitating the manipulation during the practical usethe numbers of both scales I3, I4 are suitably likewise colored,preferably differently, the windows I5, I6 may also be colored. Insteadof the figures the base may likewise be provided in color, or both, thefigures as well as the base. The masks may be opaque behind their partcorresponding to the longest possible menstrual cycle, or the rotatablediscs 29, 30 be provided with a shield (not shown) covering said part.

The lateral faces of the box formed by the outside discs 29, Sil arealong their circumference engaged by a ring 31 for closing the box, saidring being at least for the length of the supporting path I9 of thecalendar band l transparent, and provided with a window 2 before theslot 20. In Figs. 3, 4 said ring is illustrated as an independent body,it may, how-ever, also form a part of the fixed discs 23, or 24. Thering 31 is supported with the'reinforced part 31a upon the distance ring26 of the circular plates 23, 24, and is secured against rotation byprojections 40 of the plates 23, or 24. Said ring furthermore engagesgrooves 29d, 33a of both rotatable circulardiscs 29, 30. .In the ring 31there may also be provided a closable opening |31, so that the inside ofthe box may be accessible. This opening is shut by the transparentdisplaceable cover 231.

The manipulation of the feoundity calendar according to Figs. 3 to '7 isas follows:

The band I is drawn out, until in the window 2 the date of thecommencement of the menstruation appears, thereupon the discs 29, 3G areturned round, until in the Windows I5 or I6 the number of days of thelongest, and of the shortest, repectively, 0r of the constant menstrualcycle appears. Through the overlapping masks 1, 8 along thecircumference of the box the fecundity days may be read from the band I.For the continuous use the band is, with a constant adjustment of themenstrual cycles, to be drawn out only far enough to make the date ofthe commencement of the menstruation appear in the Window 2.

According to Figs. 8 and 9 the calendar band' is not drawn out of thebox, but again rolled up inside the box upon a reel 42. The manipulationof both reels I1', 42 may ensue by means of the knob 2i, connected tothe reel 42 by' means of the clutch coupling 43 under the pressure ofthe spring 44. If the knob is pressed against the action of the spring,the connection of the coupling is released, and the coupling 45 shiftedfor engaging the other reel I1 for being rolled back. The remainingembodiment is similar to the embodiment according to Figs. 3 to 7, thetransparent ring 31 being, however, constructed curve-like, in order tomagnify the figures Iof the calendar band situated beneath said ring.

Thus both windows I5, i6 may be arranged in iixed circular platessituated on the Outside, and both scales of figures may be arranged uponrotatable circular discs placed inside-of said plates, vor instead ofthe windows or masks there may also be used other indicating devices, aspointers or the like.

We claim:

l. Fecundity calendar, comprising a casing, a

band with a date calibration rolled up in said casing, a window on thecasing for indicating the date of the commencing of the menstruationappearing on said calendar band, two similar masks for indicating thefecundity days appearing on said calendar band, said masks being movablein the same direction as said calendar band, and being provided, each,with a part limiting on both sides the rangel of fecundity, said masksoverlapping each other, and both said parts indicating by their totalsurface the fecundity days. two similar xed scales with the days of thecycle from the shortest up to the longest period between twomenstruations succeeding each other, and two displaceable means, beingin fixed relation to said indicating devices for the fecundity days andadapted to co-act with one of said scales, each, for adjusting the daysof the cyclefor the shortest, and for the longest menstrual cycle,respectively.

2. Fecundity calendar, comprising a casing, a band with a datecalibration rolled up in said casing, a window on the casing forindicating the date of the commencing of the menstruation appearing onsaid calendar band, two similar masks for indicating the fecundity daysappear-` ing 'on said calendar band, said masks being movi' able in thesame direction as said calendar band, and being provided, each, with apart limiting on both sides the range of fecundity, said masksoverlapping each other, and both said parts indicatl ing' by their totalsurface the fecundity days, two

'similar-fxed rscales ywith'the days: ofthe cycle from the shortestl up.to the longest period between twolmenstruations succeeding each other,said scales being arranged in the sameV directionfas the `said masks,and two displaceable reading windows, being-in fixed relationtosaid-masks andfadapted to co-act with one of saidscales, eachf-foradjusting the days of the cycle for the shortest,V and for-thelongestmenstrual cycle, respectively.

43. Fecundity calendar according to claim 2, characterized in thatwithin said Vparts of the masksv indicating the range of fecundityconerangecomprising the specially 'fertile days Vis made prominent in adistinguishing manner. from the; remaining range of said parts.

f4. Fecundityl calendar, comprising a casingVa Y reel rotatablysupported in said casing,-a band with a date calibration rolled `upalong the circumerence of-said reel, a window in said casing forindicating the day of the commencingof the menstruation appearing uponsaid calendar band, two similar masks for indicatingV the .fecunditydaysrfappearing upon said calendar band, said masks being movable. inthe form of a circular arc concentric to said calendarand overlappingeach other, two similar scales with the dates of the cycle, each, fromthe shortest up to the longest period between two menstruationssucceeding each other, said scales being xedly arranged in the form of acircular arc for example on said casing, concentrically to the` saidmasks, two reading windows, one of which being, at a time, in fixedrelation `to one of said masks, and adapted tos, co-act with one of saidscales, for adjusting thedates of the cycle for. the shortest, and forthe longest menstrual cycle, respectively.

5,;Fecundityicalendar according to claim '/i,

characterized in :that a fixed circular path is provided as abasefor'the calendar band within the range of the cycle, in which thefecundity days may be read.

6.v lecundityv calendar as' claimed in claim'4, characterized in thatrsaid" reading windows for thescales are'provided on different sides ofsaid casing.

v'L'Fecundity calendar as claimed in claim 4, characterized in that themasksv are opaque behind their part corresponding to the longestpossiblemenstrual cycle.

8.'Fecundity calendar, comprising a flat, es- 'sentially'round casinganaxle, a reel rotatably supported in said casing upon said axle,v a knobresting' uponl saidr axle foriactuating said reel, a band with a datecalibration rolled up along the circumference' of said reel, two'xedvdiscs,'one on' each side of saidV reel, two scales with the dates ofthe. cycle from the .shortest up to the longest period Ybetween two.menstruations succeeding each other, one-of said scalesbeing 'xedlyarranged upon each of. both said circular discs in the form of acircular arc, concentrically 'to the said axle of said reel, a pair ofcircular rotatable discs, each, forming one wall of the casing; saiddiscs being arranged laterally from said xed circulardiscs, and beingprovided withv a window, each, and a pair of masks for indicating thefecundity days appearingY upon said calendar band, each of said masks.being. connected in the form of -a circular arc,.ccncentric to saidcalendar bandandto each of said rotatable circular discs, for co-actingwith one ofsaid scales for adjusting'theidatesof thecycle iortheshortest, and forthe longest menstrual cycle. respectively.

a9, Fecundityrcalendan. comprising# aJ dat, ese-1 LTI sentially-roundcasing, an axlefa reel-rotatably supported in said Vcasing uponzsaidamara-,knob

resting vupon said axle foriactuatingfsaidreel, a. band with a datecalibration rolled up along the circumference of said reel, two xedcircular discs, one on each side of said reel, a -pair of scalesv withthe dates of the cycle fromthe shortest up to the longest period betweenvtwo menstruations succeeding each other, one of said scalesbeingiixedly .arranged upon each of both said circular discs in the-form of acircular arc, concentrically tothe said aXle of said reel. a circularpairiof rotatable discs, each, forming the wall ofthe casing, each ofsaid discs being arranged laterally from said iixed circular discs andbeing provided with a window, and a' pair of masks for indicating thefecundity days appearingy upon said calendar' band, each. ofl said masksbeing connected in the form ofza circular arc, concentrically withsaidcalendar band-and to one of said rotatable circular discs, forcofacting'with one of said scales for adjusting the dates of the cyclefor the shortesty and' for the longest menstrual cycle, respectively, aswell as aring surrounding the circumference of said casing, said ringbeing at least partly transparenaso that the fecundity dates indicated`by said mask maybe seen through said transparent ring.

10. -Fecundity calendar as claimed in claim9, characterized in that saidring is connectedV to said xed circular discs.

1l. Fecundity calendar as claimed in claim 9, characterized in that saidtransparent ring is curved in its cross Asection in order toact asmagnifying lens for .thegures of the calendar band.

'12. F'ecundity calendar, comprising anat, es,F sentially roundcasing,an axle, a reel rotatably supported in said casing upon said axle, aknob' resting upon said axle for actuating said coil,. a band with adatecalibration rolled up along the circumference of said reel, two .xed,circular disks one on each side of said coil, scales with the'dates ofthefcycle from the shortest. up to the longest period between two.menstruations succeeding each other, one of saidk scales being xedlyarranged upon each of both said circular discs. inthe form of acirculararc, concentric `to the said axle of said reel, a pair ofcircular rotatable discs each forming a wall of the casing, said discsbeingarranged laterally of said. xed circular `discs and being eachprovided with .a window, and a pairV of masks for indicating thefecundity days appearing upon said calendar band, each of said pair ofmasks being connected in the form of a `circular arc, concentric to saidcalendar band, and to .one of said rotatable circular discs. forcoacting with one of. said scales foradjusting the dates of the cyclefor the short' est and for the longest rmenstrual cycle, respectively,aswell asra ring surrounding the circum- :ference of said casing, saidring being at: least partly transparent so that the fecundity datesAindicated by said masks may be seen through said transparent ring, andfurthermore lixing means-betweenv said rotatable and said xedcirculardiscs, for securing the gradual turning-of the rotatable discsfrom one of the daysof the cycle tothe followingk one. Y Y

13.- Fecundity calendar as claimed in claim l2, characterizedin thatboth fixed circularidiscs are connected to' one another, said xinglarrangement, comprising balls resiliently Supportinguponthe circularNdiscs, and recesses insaid 9 rotatable circular discs in which saidballs are engaging.

14. Fecundity calendar as claimed in claim 12, characterized in thatboth xed circular discs are connected to one another, said xing arerangement comprising balls resiliently supporting upon said circulardiscs, and recesses in said rotatable circular discs, in which saidballs are engaging, two balls, each, resting opposite each other in bothsaid circular discs, and one coil spring, each, being provided betweenboth balls, said coil springs acting with their ends upon said balls.

15. Fecundity calendar comprising a ilat substantially round casing, anaxle, a reel rotatably supported in said casing upon said axle, a knobon said axle for actuating said reel, a calendar band with a datecalibration wound up on said reel, two xed discs one on each side ofsaid reel, scales with the dates ci the cycle from the shortest up tothe longest period between two succeeding menstruations, each scalebeing xed upon one of said circular discs in the form of a circular arcconcentric to the reel axle, a pair of circular rotatable discs eachforming one wall of the casing laterally of said fixed discs and eachprovided with a window, a pair of masks for indicating the fecunditydays on said band, each mask being connected in the form of a circulararc concentric to said band and to one of said rotatable discs forcoacting with one` scale, and a spring pressing said reel against aiixed disc, and another spring for braking the band.

16. Fecundity calendar comprising a casing, a reel rotatable in saidcasing, a calendar band with a date calibration wound on said reel, awindow in said casing for indicating the day of the commencement of themenstruation appearing on the band, two similar masks for indicating thefecundity days on the band, said masks being movable in the form of anarc concentric with said band and overlapping each other, two similarscales with the dates of the cycle each from the shortest up to thelongest period between succeeding menstruations, said scales beingixedly arranged in the form of an arc concentric to said mask, tworeading windows, one being at a time in xed relation to one of saidmasks and coacting with a scale and another reel for winding up the bandunwound from said first reel.

17. Fecundity calendar according to claim 16 and wherein the other reelis concentric with the first reel.

18. A iecundity calendar comprising a casing, a calendar band movablelengthwise in the casing and provided with a scale oi ordinalsrepresenting the days of at least one month of thirty-one days windowmeans rigid with the casing and in the path of the band and registrablewith an ordinal thereon denoting the commencement of menstruation, apair of masks each adjacent to an edge of the band and movablerelatively to the casing and lengthwise of the band to positions eachindicating the shortest and longest range respectively of fecundity daysappearing on the band, a pair of similar fixed scales of ordinalsrepresenting at least some of the days in a menstrual cycle and eachscale on the casing to one side of the band, and means each displaceableon the casing and lengthwise of a scale and in fixed relation to a maskand when registering with an ordinal of a scale denoting the end of thecycle of menstruation beginning with the ordinal in registering with thewindow means.

THERESIA SCHENK. MARIA SPRUNG.

REFERENCES CITED UNITED STATES PATENTS Name Date Rogers May 16, 1938Number

